Unmanned aerial vehicles typically provide data-link communications through an airborne data terminal (ADT). The ADT usually consists of a transmitter, receiver and an antenna assembly. The antennas used are medium or high-gain directional antennas working in combination with omni-directional antennas. The directional antenna is normally a printed array or horn antenna which requires the use of a mechanical positioner to aim the antenna at a remote transmitting or receiving station. The positioning of the antenna is controlled by manipulating the positioner via the data-link control in accordance to either operator-commanded positions or azimuth-based positions calculated by using the data received from the Global Positioning System (GPS).
However, the mechanical positioners used to aim the directional antenna are large and heavy and are capable of only limited elevation coverage. Further, they need to be situated external to the aircraft body in order to provide full azimuth coverage and to avoid aircraft body obstructions. FIG. 1 illustrates a typical mounting position of airborne data terminal (ADT) 101 that includes a mechanical positioner on aerial vehicle 103. The external positioning of the ADT increases aircraft drag and, in some aircraft orientations, causes certain areas to have limited or obscured RF transmission or reception due to the aircraft body obstruction. Unmanned ground vehicles currently use similar structures though these rely mostly on low gain omni-directional antennas. If communications with multiple remote data terminals is desired, then multiple directional antennas must be used. This, in turn, increases the complexity of the required mechanical positioner as well as its control mechanism while continuing to suffer obscurations and drags.